This invention relates to electronic connectors and, in particular, to a dual-beam receptacle socket contact for conductively engaging a pin contact to couple the pin contact to an electrical circuit. More particularly, this invention relates to a socket contact having its pin-engaging beams oriented to lie in orthogonal planes and a flat pattern for producing a plurality of such socket contacts.
Receptacle-type socket contacts are typically produced by stamp-forming suitable sheet material to provide a carrier strip and a plurality of flat socket contacts connected to the carrier strip at uniformly spaced-apart junction points along an edge of the carrier strip. A series of dies can be used to accomplish the stamp-forming step. A rotatable sprocket wheel or the like can engage perforations formed in the carrier strip and rotate to move the sheet material appended to the strip through the series of dies to produce a flat pattern. Once stamped, the flat socket contacts included in the flat pattern are bent or otherwise formed to assume a final shape configured to provide receptacles for receiving pin contacts.
Once the socket contacts are fully formed, they are ready for insertion into contact-receiving openings formed in an electrical connector housing. It is desirable to "gang-insert" all of the fully formed socket contacts provided by a flat pattern into the contact-receiving openings in an electrical connector housing simultaneously to produce an electrical connector in the most efficient manner possible. In certain applications, it is best to "seed" all of the socket contacts in the connector housing openings first and then sever the carrier strip at junctions between the carrier strip and the solder tail of each socket contact to leave the socket contacts in their mounted positions in the connector housing. In other applications, it is desirable to grip each of the socket contact solder tails by means of a separate clamping fixture and then sever the carrier strip so that the clamping fixture can be used instead of the carrier strip to gang-insert the socket contacts into the connector housing openings.
A conventional electrical connector housing is formed to include an array of uniformly spaced-apart contact-receiving openings. In such a connector housing, the "center-to-center" spacing of adjacent pairs of contact-receiving openings is constant. It is best to configure the flat pattern so that the center-to-center spacing between adjacent socket contacts on the carrier strip or the like is equivalent to the center-to-center spacing of the contact-receiving openings to ensure that the socket contacts can be gang-inserted into the openings formed in the connector housing. Such a configuration will result in a flat pattern that is compatible with a particular style of connector housing.
Problems arise in seeding conventional socket contacts into connector housing openings if the center-to-center spacing of the conventional socket contacts is greater than the center-to-center spacing of the contact-receiving openings in the connector housing. For example, a conventional flat pattern having a plurality of socket contacts arranged on 0.170 inch center-to-center spacing cannot be gang-inserted into a connector housing having openings arranged on 0.100 inch center-to-center spacing because of the spacing mismatch between the "socket" centers and the "opening" centers. In such a circumstance, it is generally necessary to seed each socket contact individually in a selected connector housing opening. Even though use of this procedure might not result in a lot of wasted, unused, flat pattern sheet material, it is nevertheless inefficient and uneconomical.
Alternatively, it is known to configure a flat pattern to have a center spacing between sockets that is twice the dimension of the center spacing between connector housing openings so that all odd and even-numbered connector housing openings can be seeded with a socket contact following the completion of two successive gang-insertion steps. In a first step, a first flat pattern is used to gang-insert all of its socket contacts into odd-numbered openings skipping the even-numbered openings. In a second step, a second flat pattern is used to gang-insert all of its socket contacts into the unfilled even-numbered openings. For example, a first conventional flat pattern having a plurality of socket contacts arranged on 0.200 inch center-to-center spacing can be used to seed the odd-numbered openings of a connector housing having openings arranged on 0.100 inch center-to-center spacing and a second conventional flat pattern of identical construction next can be used to seed the unfilled even-number openings of the same housing. In this case, a significant amount of valuable flat pattern sheet material is unused in the stamp-forming step and thereby wasted because of the need to spread the socket contacts far enough apart on the flat pattern to double the center-to-center spacing of the housing openings. Further, although automatic handling equipment can be employed to seed the connector housing automatically using two flat patterns in succession, the seeding process is slowed considerably because two passes are necessary to fill all of the odd-numbered and even-numbered openings.
Turning to another matter, it will be appreciated that socket contacts are susceptible to disfunction problems in use caused by shock or vibration. For example, the electrical connection between a socket contact and a pin contact inserted therein can fail intermittently. A dual-beam receptacle socket contact includes a pair of beams configured to trap a pin contact therebetween to establish an electrical connection between the pin contact and the socket contact. In use, these beams are often exposed to shock and vibration sufficient to cause each beam to bounce or vibrate at a characteristic frequency. The electrical connection between the pin and socket contacts can be broken intermittently if the contacts are exposed to shock or vibration of a type which causes each beam to vibrate at the same frequency. Development of a dual-beam receptacle socket which is configured to minimize the chance that the normal frequency of each beam is the same would avoid shortcomings of conventional dual beam receptacle sockets known to experience "contact bounce" or "electrical intermittency" when subjected to shock or vibration.
One object of the present invention is to provide a socket contact that is better able to maintain electrical contact with a pin contact inserted therein when subjected to shock or vibration.
Another object of the present invention is to provide a socket contact that is produced easily by stamp-forming sheet material without wasting valuable sheet material during manufacture of the flat pattern of the socket contact.
Yet another object of the present invention is to provide a socket contact having a pair of beams which are shaped and arranged to permit nesting of a series of socket contacts in a flat pattern prior to separation of the socket contacts from a carrier strip so as to conserve the valuable sheet material from which the flat pattern is made.
Still another object of the present invention is to mount socket contacts in an electrical connector housing by developing a flat pattern having a series of socket contacts arranged on a center-to-center spacing that is equivalent to the center-to-center spacing of the socket contact-receiving apertures formed in an electrical connector housing.
According to the present invention, an electrical socket contact is provided for conductively engaging a pin contact. The socket contact includes a body portion having a tail for connection to an electrical circuit and a pair of beams. A first of the beams has a proximal end cantilevered to the body portion and a distal end configured to provide a first contact mating surface. A second beam is arranged to lie alongside the first beam. The second beam includes a blade having a second contact mating surface and a support arm having a proximal portion cantilevered to the body portion and a distal portion. The blade is coupled to the support arm at one side of the distal portion to lie at an angle to the distal portion so as to support the second contact mating surface in opposing relation to the first contact mating surface to define a pin contact-receiving space therebetween.
In preferred embodiments, the first beam is configured to lie substantially in a first horizontal plane and the second beam is configured to lie substantially in a vertical plane in spaced-apart relation to the first beam. The blade is configured to lie substantially in a second horizontal plane underlying the distal end of the first beam in spaced-apart relation to the first horizontal plane. Also, the blade is arranged to lie at about a right angle to the distal portion of the support arm.
Advantageously, the shape, length, and mass of the first and second beams are different to ensure that the chance of the normal frequency of each beam being the same is remote. These beam configurations reduce the likelihood that the socket contact will suffer electrical intermittency problems when subjected to shock or vibration.
A flat pattern is also disclosed for providing a plurality of electrical socket contacts. The flat pattern includes a carrier strip and a plurality of socket contacts connected to the strip. The carrier strip has a plurality of junction points uniformly spaced along an edge of the carrier strip so that each pair of adjacent junction points is separated by a predetermined dimension.
Each socket contact has a longitudinal axis and includes a body portion having a tail connected to the carrier strip at one of the junction points. Each junction point has a tail of one socket contact connected thereto.
First and second beams are coupled to the body portion to provide a pair of pin contact-engaging members. Each socket contact has a maximum transverse width dimension in its flat position greater than the predetermined dimension between each pair of adjacent junction points on the carrier strip. Nevertheless, each contact can be bent and manipulated from its stamped "flat pattern" shape to align the first beam in the first horizontal plane and the support arm of the second beam in a vertical plane as described above to define a pin contact-receiving space between the first beam and the blade of the second beam.
Essentially, the body portions of each pair of adjacent socket contacts are arranged in uniformly spaced-apart relation so that the center-to-center spacing of the socket contacts matches the center-to-center spacing of the contact-receiving openings in the electrical contact housing. Further, the first beam of each socket contact is arranged to lie in nested relation to the second beam of one of its adjacent socket contacts to conserve valuable sheet material during manufacture of the flat pattern.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.